How much would a bunny cost?

I live in Boonville, IN but would drive to Evansville. My parents want to surpise my little sister with a bunny rabbit to teach her to care for her own pet. We were thinking about adopting one from Petsmart. Or from someone selling bunnies. Or maybe from Harp's Pets. Anyways, my parents want me to ask around how much one would cost.